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Faculty Profile: Nicholas Meskhidze

Atmospheric scientist

School of Marine Earth and Atmospheric Sciences, North Carolina State University

This profile is part of a collection of profiles of faculty members in the geosciences. The collection focuses on faculty whose teaching and research connect to the future of science. This profile was created in 2007.

Teaching

What are your teaching responsibilities?

I teach two courses per year; this year they are atmospheric physics and advanced physical meteorology.

How does your teaching relate to traditional geology?

My teaching is traditional in many ways. My students learn about climate change, a standard topic in geoscience. They examine real data to make connections between theory and observations of the real world. They learn to derive equations, to better understand the underlying theory.

How does it take geoscience in new directions? How does it take your department in new directions?

I work to incorporate new discoveries and new ideas into my classes, as they are developed. Geoscience is a dynamic field, and as our understanding of Earth's systems evolves, I bring that into the classroom. For example, real-time satellite data provides exciting opportunities for understanding atmospheric and oceanic processes. This is one tool I use to help students learn about complex interactions between the hydrosphere, atmosphere, and biosphere. This focus on processes involving such interactions is a growing area of study in the geosciences.

Research

What are your research interests and activities?

My PhD research was in atmospheric chemistry, but my current interests have expanded to ocean-atmosphere-biosphere interaction. More specifically, one focus of my research is the interrelationship between pollution, the transport of terrestrial dust into the ocean, and biological blooms. This is important because oceanic productivity (an increase in biological activity) strongly affects the global carbon cycle, which in turn impacts global climate. For example, a biological bloom can be a carbon sink; many marine organisms use carbon dioxide to build their shells. When they die, some fraction of carbon sinks to the longer-lived carbon reservoirs of the deep ocean and ocean sediments. Thus, a bloom of such organisms may remove carbon dioxide from the atmosphere.

In theory, an input of dust into the parts of the ocean where micronutrient iron is limiting biological productivity should lead to a bloom. It doesn't always do so. That seems to be because the iron is not always bio-available, meaning the organisms can't make use of it. Mixing of mineral dust with anthropogenic air pollutants (e.g., sulfur dioxide) may change the chemical composition of iron and make it bioavailable; eastern Asia is an example of this. However, dust emanating from pristine environments, such as the southern oceans, may not lead to a bloom. So it appears that there is a connection between pollution and the bio-availability of iron.

Furthermore, some biological blooms cannot be accounted for solely on the basis of iron from terrestrial dust. Instead, these blooms appear to be the result of iron brought to the near-surface by upwelling. Where upwelling is the source of iron in the ocean, iron correlates well with ocean surface temperatures, because upwelling brings nutrients to the surface in colder water.

I use numerical models, in conjunction with satellite data analyses, to investigate these relationships.

How does your research relate to traditional geology?

My research is traditional in that it focuses on questions of forcing and feedback. The input of terrestrial dust, including iron, into the ocean is a forcing mechanism: it causes a biological bloom. Biological bloom can cause an indirect or secondary change (feedback). By modulating cloud properties it can affect the amount of sunlight and the quantity of dissolved iron (more iron dissolves in clouds) reaching the ocean surface.

How does it take geoscience in new directions? How does it take your department in new directions?

The availability of high-quality satellite data makes it possible to answer different kinds of questions than were previously possible. For example, we can use NASA time delay data (from two different satellites, orbiting above the same region) to quantify cloud formation in areas where no ground measurements are available. This use of a vast data set to quantify atmospheric processes is relatively new. Similarly, we are just beginning to learn about many atmosphere-ocean-biosphere interactions; geoscientists have traditionally focused on just one of these spheres, rather than on how they affect each other.

Connections Between Teaching & Research

Interestingly, it was a class research project I did in graduate school that led to my current research.... So in a sense, I've been making connections between classroom learning and research throughout my career. I also have my students conduct research projects. These projects require the students to conduct independent research, analyzing and interpreting data sets related to a topic of their own choosing that we cover in the course. I think this process, engaging with real data, is an invaluable learning experience.